In order to carry about, for the user, cellular telephones or mobile phones, there are actually different types of cases which the user can wear for example at the belt or over one shoulder. No one of the devices actually known allows the possibility of quickly and easily setting the cellular telephone to its use condition and then as well quickly and easily setting it back to rest, and no one of the known devices allows to carry the cellular telephone in such a position to allow the user to hear a call, particularly in presence of great noise. The invention intends to solve these and other problems through the following solution idea. The small size cellular telephone is fixed on a telescopic slide sliding on a guide longitudinally to be secured at the wrist of the arm of the user. In this position, when the cellular telephone receives a call and has the vibration signaller warning system activated, the vibrations are easily transmitted to the slides and guide system and from this latter to the wrist of the user who can this way instantaneously notice the call state, even in a noisy place. By catching the cellular telephone with the free hand, the user can extend the guides and quickly bring the cellular telephone to the palm of the hand to use it. When the conversation is over, the cellular telephone can be as well quickly taken back to the backward rest position on the wrist. Suitable means are provided to keep the slides in the backward rest position and if required also in the extended use position of the cellular telephone. Further features of the invention and the advantages deriving therefrom, will better appear from the following description of a preferred embodiment of same, illustrated, by way of non-limiting example, in the figures of the attached sheets of drawings, in which: